NSK Bearings

Rolling Bearings

Page No.

Technical Information Deep Groove Ball Brgs. Angular Contact Ball Brgs. Self-Aligning Ball Brgs. Cylindrical Roller Brgs. Tapered Roller Brgs. Spherical Roller Brgs. Thrust Brgs. Needle Roller Brgs. Ball Brg. Units Plummer Blocks Cylindrical Roller Brgs. for Sheaves Roll-Neck Brgs. (4-Rows) Railway Rolling Stock Brgs. Balls and Rollers Accessories for Rolling Brgs. NSK Products and Appendices

A7 B4 B46 B72 B80 B106 B178 B202 B240 B276 B300 B322 B330 B342

Tech. Info.

Thrust Brgs.

Sheaves

Roll Neck Railway

Sleeves

B352 C1Appendices

Rolling Bearings

CAT. No. E1102e

Introduction to Revised NSK Rolling Bearing Catalog (CAT.No.E1102e)We want to thank you for your interest in this edition of our Rolling Bearing Catalog. It has been revised with our customers in mind, and we hope it fills your needs. Recently, technology has been advancing at a remarkable pace, and with it has come a host of new products in many fields including computers, office automation, audio-visual equipment, medical equipment, and many others. These striking innovations present a challenge to bearing manufacturers since there are ever increasing demand to offer bearings with higher performance, accuracy, and reliability. Manufacturers of diverse equipment have many different bearing requirements including higher speeds, less torque, less noise and vibration, zero maintenance, survival in harsh environments, integration into units, and many more. This catalog was revised to reflect the growing number of NSK products and certain revisions in JIS and ISO and to better serve our customers. The first part contains general information about rolling bearings to facilitate selection of the most appropriate type. Next supplementary technical information is provided regarding bearing life, load ratings, limiting speeds, handling and mounting, lubrication, etc. Finally, the catalog presents extensive tables containing most bearing numbers and showing dimensions and pertinent design data listed in the order of increasing bore size. Data in the table are given in both the international Unit System (SI) and Engineering Unit System (Gravitational System of Units). We hope this catalog will allow you to select the optimum bearing for your application. However, if assistance is required, please contact NSK, and the companys engineers and computer programs can quickly supply the information you need.

NSK Web site A http://www.nsk.com

CONTENTSTECHNICAL INFORMATION1 Pages TYPES AND FEATURES OF ROLLING BEARINGS A 7 1.1 Design and Classification A 7 1.2 Characteristics of Rolling Bearings A 7 BEARING SELECTION PROCEDURE A16 SELECTION OF BEARING TYPE A18 3.1 Allowable Bearing Space A18 3.2 Load Capacity and Bearing Types A18 3.3 Permissible Speed and Bearing Types A18 3.4 Misalignment of Inner/Outer Rings and Bearing Types A18 3.5 Rigidity and Bearing Types A19 3.6 Noise and Torque of Various Bearing Types A19 3.7 Running Accuracy and Bearing Types A19 3.8 Mounting and Dismounting of Various Bearing Types A19 SELECTION OF BEARING ARRANGEMENT A20 4.1 Fixed-End and Free-End Bearings A20 4.2 Examples of Bearing Arrangements A21 SELECTION OF BEARING SIZE A24 5.1 Bearing Life A24 5.1.1 Rolling Fatigue Life and Basic Rating Life A24 5.2 Basic Load Rating and Fatigue Life A24 5.2.1 Basic Load Rating A24 5.2.2 Machinery in which Bearings are Used and Projected Life A24 5.2.3 Selection of Bearing Size Based on Basic Load Rating A25 5.2.4 Temperature Correction for Basic Load Rating A26 5.2.5 Correction of Basic Rating Life A27 5.3 Calculation of Bearing Loads A28 5.3.1 Load Factor A28 5.3.2 Bearing Loads in Belt or Chain Transmission Applications A28 5.3.3 Bearing Loads in Gear Transmission Applications A29 5.3.4 Load Distribution on Bearings A29 5.3.5 Average of Fluctuating load A29 Pages 5.4 Equivalent LoadA30 5.4.1 Calculation of Equivalent Loads A31 5.4.2 Axial Load Components in Angular Contact Ball Bearings and Tapered Roller Bearings A31 5.5 Static Load Ratings and Static Equivalent Loads A32 5.5.1 Static Load Ratings A32 5.5.2 Static Equivalent Loads A32 5.5.3 Permissible Static Load Factor A32 5.6 Maximum Permissible Axial Loads for Cylindrical Roller Bearings A33 5.7 Examples of Bearing CalculationsA34 6 LIMITING SPEED A37 6.1 Correction of Limiting Speed A37 6.2 Limiting Speed for Rubber Contact Seals for Ball Bearings A37 12 7 4 BOUNDARY DIMENSIONS AND IDENTIFYING NUMBERS FOR BEARINGS A38 7.1 Boundary Dimensions and Dimensions of Snap Ring Grooves A38 7.1.1 Boundary Dimensions A38 7.1.2 Dimensions of Snap Ring Grooves and Locating Snap Rings A38 7.2 Formulation of Bearing Numbers A54 13 8 BEARING TOLERANCES A58 8.1 Bearing Tolerance Standards A58 8.2 Selection of Accuracy Classes A81 FITS AND INTERNAL CLEARANCES A82 9.1 Fits A82 9.1.1 Importance of Proper Fits A82 9.1.2 Selection of Fit A82 9.1.3 Recommended Fits A83 9.2 Bearing Internal Clearances A88 9.2.1 Internal Clearances and Their Standards A88 9.2.2 Selection of Bearing Internal Clearances A94 PRELOAD A96 10.1 Purpose of Preload A96 10.2 Preloading Methods A96 10.2.1 Position Preload A96 10.2.2 Constant-Pressure Preload A96 14 Pages 10.3 Preload and Rigidity A96 10.3.1 Position Preload and Rigidity A96 10.3.2 Constant-Pressure Preload and Rigidity A97 10.4 Selection of Preloading Method and Amount of Preload A97 10.4.1 Comparison of Preloading Methods A97 10.4.2 Amount of Preload A98 11 DESIGN OF SHAFTS AND HOUSINGS A100 11.1 Accuracy and Surface Finish of Shafts and Housings A100 11.2 Shoulder and Fillet Dimensions A100 11.3 Bearing Seals A102 11.3.1 Non-Contact Types Seals A102 11.3.2 Contact Type Seals A104 LUBRICATION A105 12.1 Purposes of Lubrication A105 12.2 Lubricating Methods A105 12.2.1 Grease Lubrication A105 12.2.2 Oil Lubrication A107 12.3 Lubricants A110 12.3.1 Lubricating Grease A110 12.3.2 Lubricating Oil A112 BEARING MATERIALS A114 13.1 Materials for Bearing Rings and Rolling Elements A114 13.2 Cage Materials A115 BEARING HANDLING A116 14.1 Precautions for Proper Handling of Bearings A116 14.2 Mounting A116 14.2.1 Mounting of Bearings with Cylindrical Bores A116 14.2.2 Mounting of Bearings with Tapered Bores A118 14.3 Operation Inspection A118 14.4 Dismounting A121 14.4.1 Dismounting of Outer Rings A121 14.4.2 Dismounting of Bearings with Cylindrical Bores A121 14.4.3 Dismounting of Bearings with Tapered Bores A122 14.5 Inspection of Bearings A123 14.5.1 Bearing Cleaning A123 14.5.2 Inspection and Evaluation of Bearings A123 Pages 14.6 Maintenance and Inspection A124 14.6.1 Detecting and Correcting Irregularities A124 14.6.2 Bearing Failures and Countermeasures A124 15 TECHNICAL DATA A126 15.1 Axial Displacement of Bearings A128 15.2 Fits A130 15.3 Radial and Axial Internal Clearances A132 15.4 Preload and Starting Torque A134 15.5 Coefficients of Dynamic Friction and Other Bearing Data A136 15.6 Brands and Properties of Lubricating Greases A138

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BEARING TABLESCONTENTS B2

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INTRODUCTION OF NSK PRODUCTS-APPENDICESCONTENTS C 1 Photos of NSK Products C 2 Appendix 1 Conversion from SI (International Units) System C 8 Appendix 2 N-kgf Conversion Table C10 Appendix 3 kg-lb Conversion Table C11 Appendix 4 C-F Temperature Conversion Table C12 Appendix 5 Viscosity Conversion Table C13 Appendix 6 Inch-mm Conversion Table C14 Appendix 7 Hardness Conversion Table C16 Appendix 8 Physical and Mechanical Properties of Materials C17 Appendix 9 Tolerances for Shaft Diameters C18 Appendix 10 Tolerances for Housing Bore Diameters C20 Appendix 11 Values of Standard Tolerance Grades IT C22 Appendix 12 Speed Factor fn C24 Appendix 13 Fatigue Life Factor fh and Fatigue Life L-Lh C25 Appendix 14 Index of Inch Design Tapered Roller Bearings C26

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A4

A5

1.TYPES AND FEATURES OF ROLLING BEARINGS1.1 Design and ClassificationRolling bearings generally consist of two rings, rolling elements, and a cage, and they are classified into radial bearings or thrust bearings depending on the direction of the main load. In addition, depending on the type of rolling elements, they are classified into ball bearings or roller bearings, and they are further segregated by differences in their design or specific purpose. The most common bearing types and nomenclature of bearing parts are shown in Fig.1.1, and a general classification of rolling bearings is shown in Fig. 1.2. (2) With the advancement of worldwide standardization, rolling bearings are internationally available and interchangeable. (3) Maintenance, replacement, and inspection are easy because the structure surrounding rolling bearings is simple. (4) Many rolling bearings are capable of taking both radial and axial loads simultaneously or independently. (5) Rolling bearings can be used under a wide range of temperatures. (6) Rolling bearings can be preloaded to produce a negative clearance and achieve greater rigidity. Furthermore, different types of rolling bearings have their own individual advantages. The features of the most common rolling bearings are described on Pages A10 to A12 and in Table 1.1 (Pages A14 and A15).

1.2 Characteristics of Rolling BearingsCompared with plain bearings, rolling bearings have the following major advantages: (1) Their starting torque or friction is low and the difference between the starting torque and running torque is small.

Width Snap Ring Cage Rivet Outside Dia. Bore Dia. Ball Pitch Diameter Outer Ring Inner Ring

Contact Angle Outer Ring Front Face Inner Ring Back Face Effective Load Center Outer Ring Back Face Inner Ring Front Face

Inner Ring Rib Roller Inscribed Circle Dia.

Outer Ring Rib L-Shaped Thrust Collar

Inner Ring Raceway Outer Ring Raceway

Side Face Shield Chamfer Dimension

Cylindrical Roller Cross-Face Width

Single-Row Deep Groove Ball BearingBearing Width Stand out

Single-Row Angular Contact Ball Bearing

Cylindrical Roller BearingA Ra lign diu ing s Se atBore Dia. Shaft Washer Ball Housing Washer Aligning Seat Washer Housing Washer Bore Dia. Outside Dia. Aligning Seat Washer O.D.

Cone Back Face Rib Effective Load Center Cone Back Face Cup Front Face

Contact Angle

Tapered Bore

Adapter

Tapered Roller

Cone Front Face Rib

Lock Washer Nut Sleeve

Aligning Seat Center Height

Height

Cone Front Face Cup Back Face

Inner Ring Spherical Roller Outer Ring

Tapered Roller Bearing

Spherical Roller Bearing

Single-Direction Thrust Ball Bearing

Fig. 1.1 Nomenclature for Bearing Parts

A6

A7

TYPES AND FEATURES OF ROLLING BEARINGS

ROLLING BEARINGS(Radial Bearings) Single Row Double Row (Thrust Bearings) Single Direction Thrust Ball Bearings Ball Bearings Angular Contact Thrust Ball Bearings Ball Bearings Cylindrical Roller Thrust Bearings Needle Roller Thrust Bearings Tapered Roller Thrust Bearings Spherical Thrust Roller Bearings Double Direction

Deep Groove Ball Bearings

Single-Direction Thrust Ball Bearing

Deep Groove Ball BearingSingle Row Double Row Matched

Magneto Bearings

Cylindrical Roller Thrust Bearing

Angular Contact Ball Bearing

Angular Contact Ball Bearings

Tapered Roller Thrust Bearing

Three- Point/Four-Point Contact Ball Bearings

Roller Bearings

Self-Aligning Ball Bearing

Self-Aligning Ball Bearings Ball Bearings for Bearing Units Single Row Double Row

Spherical Thrust Roller Bearing

Cylindrical Roller Bearing

Cylindrical Roller Bearings Long-Roller Bearings Needle Roller Bearings Roller Bearings Bearings for Specific Uses Tapered Roller Bearings

Automotive Clutch Release Bearings Automotive Water Pump Bearings Rolling Stock Axle Bearings Crane-Sheave Bearings Chain Conveyor Bearings

Sealed Axle Bearing

Needle Roller BearingSingle Row

Cylindrical Roller Bearing for Sheaves

Tapered Roller Bearing

Double Row Four Row

Others Spherical Roller Bearings

Spherical Roller Bearing

Fig. 1.2 Classification of

Rolling Bearings

A8

A9


Single-Row Deep Groove Ball Bearings

Single-row deep groove ball bearings are the most common type of rolling bearings. Their use is very widespread. The raceway grooves on both the inner and outer rings have circular arcs of slightly larger radius than that of the balls. In addition to radial loads, axial loads can be imposed in either direction. Because of their low torque, they are highly suitable for applications where high speeds and low power loss are required. In addition to open type bearings, these bearings often have steel shields or rubber seals installed on one or both sides and are prelubricated with grease. Also, snap rings are sometimes used on the periphery. As to cages, pressed steel ones are the most common.

Double-Row Double-row angular contact ball bearings are basically two single-row angular contact ball Angular Contact bearings mounted back-to-back except that they have only one inner ring and one outer ring, each Ball Bearings having raceways. They can take axial loads in either direction.

Magneto Bearings

The inner groove of magneto bearings is a little shallower than that of deep groove bearings. Since the outer ring has a shoulder on only one side, the outer ring may be removed. This is often advantageous for mounting. In general, two such bearings are used in duplex pairs. Magneto bearings are small bearings with a bore diameter of 4 to 20 mm and are mainly used for small magnetos, gyroscopes, instruments, etc. Pressed brass cages are generally used.

Four-Point Contact Ball Bearings

The inner and outer rings of four-point contact ball bearings are separable because the inner ring is split in a radial plane. They can take axial loads from either direction. The balls have a contact angle of 35 with each ring. Just one bearing of this type can replace a combination of face-to-face or back-to-back angular contact bearings. Machined brass cages are generally used.

Single-Row Individual bearings of this type are capable of taking radial loads and also axial loads in one Angular Contact direction. Four contact angles of 15, 25, 30, and 40 are available. The larger the contact angle, Ball Bearings the higher the axial load capacity. For high speed operation, however, the smaller contact angles are preferred. Usually, two bearings are used in duplex pairs, and the clearance between them must be adjusted properly. Pressed-steel cages are commonly used, however, for high precision bearings with a contact angle less than 30, polyamide resin cages are often used.

Self-Aligning Ball Bearings

The inner ring of this type of bearing has two raceways and the outer ring has a single spherical raceway with its center of curvature coincident with the bearing axis. Therefore, the axis of the inner ring, balls, and cage can deflect to some extent around the bearing center. Consequently, minor angular misalignment of the shaft and housing caused by machining or mounting error is automatically corrected. This type of bearing often has a tapered bore for mounting using an adapter sleeve.

Duplex Bearings A combination of two radial bearings is called a duplex pair. Usually, they are formed using angular contact ball bearings or tapered roller bearings. Possible combinations include face-to-face, which have the outer ring faces together (type DF), back-to-back (type DB), or both front faces in the same direction (type DT). DF and DB duplex bearings are capable of taking radial loads and axial loads in either direction. Type DT is used when there is a strong axial load in one direction and it is necessary to impose the load equally on each bearing.

Cylindrical In bearings of this type, the cylindrical rollers are in linear contact with the raceways. They have a Roller Bearings high radial load capacity and are suitable for high speeds. There are different types designated NU, NJ, NUP, N, NF for single-row bearings, and NNU, NN for double-row bearings depending on the design or absence of side ribs. The outer and inner rings of all types are separable. Some cylindrical roller bearings have no ribs on either the inner or outer ring, so the rings can move axially relative to each other. These can be used as free-end bearings. Cylindrical roller bearings, in which either the inner or outer rings has two ribs and the other ring has one, are capable of taking some axial load in one direction. Double-row cylindrical roller bearings have high radial rigidity and are used primarily for precision machine tools. Pressed steel or machined brass cages are generally used, but sometimes molded polyamide cages are also used.

A 10

A 11


Needle Needle roller bearings contain many slender rollers with a length 3 to 10 times their diameter. As a Roller Bearings result, the ratio of the bearing outside diameter to the inscribed circle diameter is small, and they have a rather high radial load capacity. There are numerous types available, and many have no inner rings. The drawn-cup type has a pressed steel outer ring and the solid type has a machined outer ring. There are also cage and roller assemblies without rings. Most bearings have pressed steel cages, but some are without cages.

Single-Direction Thrust Ball Bearings

Tapered Bearings of this type use conical rollers guided by a back-face rib on the cone. These bearings are Roller Bearings capable of taking high radial loads and also axial loads in one direction. In the HR series, the rollers are increased in both size and number giving it an even higher load capacity. They are generally mounted in pairs in a manner similar to single-row angular contact ball bearings. In this case, the proper internal clearance can be obtained by adjusting the axial distance between the cones or cups of the two opposed bearings. Since they are separable, the cone assemblies and cups can be mounted independently. Depending upon the contact angle, tapered roller bearings are divided into three types called the normal angle, medium angle, and steep angle. Double-row and four-row tapered roller bearings are also available. Pressed steel cages are generally used.

Single-direction thrust ball bearings are composed of washer-like bearing rings with raceway grooves. The ring attached to the shaft is called the shaft washer (or inner ring) while that attached to the housing is called the housing washer(or outer ring). In double-direction thrust ball bearings, there are three rings with the middle one (center ring) Double-Direction being fixed to the shaft. There are also thrust ball bearings with an aligning seat washer beneath the housing washer in Thrust Ball order to compensate for shaft misalignment or mounting error. Bearings Pressed steel cages are usually used in the smaller bearings and machined cages in the larger

Spherical These bearings have barrel-shaped rollers between the inner ring, which has two raceways, and Roller Bearings the outer ring which has one spherical raceway. Since the center of curvature of the outer ring raceway surface coincides with the bearing axis, they are self-aligning in a manner similar to that of self-aligning ball bearings. Therefore, if there is deflection of the shaft or housing or misalignment of their axes, it is automatically corrected so excessive force is not applied to the bearings. Spherical roller bearings can take, not only heavy radial loads, but also some axial loads in either direction. They have excellent radial load-carrying capacity and are suitable for use where there are heavy or impact loads. Some bearings have tapered bores and may be mounted directly on tapered shafts or cylindrical shafts using adapters or withdrawal sleeves. Pressed steel and machined brass cages are used.

Spherical Thrust These bearings have a spherical raceway in the housing washer and barrel-shaped rollers obliquely Roller Bearings arranged around it. Since the raceway in the housing washer in spherical, these bearings are selfaligning. They have a very high axial load capacity and are capable of taking moderate radial loads when an axial load is applied. Pressed steel cages or machined brass cages are usually used.

A 12

A 13


Table 1. 1 Types and CharacteristicsDeep Groove Ball Bearings Magneto Bearings Angular Contact Ball Bearings Double-Row Angular Contact Ball Bearings Duplex Angular Contact Ball Bearings Four-Point Contact Ball Bearings SelfAligning Ball Bearings Cylindrical Roller Bearings Double-Row Cylindrical Roller Bearings Cylindrical Roller Bearings with Single Rib

of Rolling BearingsCylindrical Roller Bearings with Thrust Collars Needle Roller Bearings Tapered Roller Bearings Double-and Multiple-Row Tapered Roller Bearings Spherical Roller Bearings Thrust Ball Bearings Thrust Ball Bearings with Aligning SeatDoubleDirection Angular Contact Thrust Ball Bearings

Bearing Types Features

Cylindrical Roller Thrust Bearings

Tapered Roller Thrust Bearings

Spherical Thrust Roller Bearings

Page No.

Radial Loads Load Capacity Axial Loads Combined Loads High Speeds High Accuracy Low Noise and Torque Rigidity Angular Misalignment Self-Aligning Capability Ring Separability Fixed-End Bearing Free-End Bearing Tapered Bore in Inner RingContact angles of 15o, 25o o o 30 , and 40 . Two bearings are usually mounted in opposition. Clearance adjustment is necessary.

A18 A37 A19 A58 A81 A19 A19 A96

A18Blue pages of each brg. type

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A18 A19 A20 A20~ ~A21 A20~ ~A27 A800 A118 A122

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i Combination of DF and DT pairs is possible, but use on free-end is not possible. Contact angle of 35o

i Two bearings are usually mounted in opposition. Clearance adjustment is necessary. Including NNU type Including NUP type

i Including needle roller thrust bearings

Two bearings are usually mounted in opposition.

Remarks

Including NF type

Page No.Excellent i Applicable

B5 B31 Good

B5 B28

B47 Fair

B47 B66

B47 Poor

B47 B68

B73

B81

B81 B106

KH, KV types are also available but use on free-end is impossible.

Including N type

B81 Two directions

B81

B111

B111 B172 B295

B179

B203

B203

B231

B203 B220

B203 B224

One direction only I Applicable, but it is necessary to allow shaft contraction/elongation at fitting surfaces of bearings.

Impossible

A 14

To be used with oil lubrication

A 15

2. BEARING SELECTION PROCEDUREEvaluation of accuracy

Examination of fitting Running accuracy A Rotational stability A Torque fluctuationA

The number of applications for rolling bearings is almost countless and the operating conditions and environments also vary greatly. In addition, the diversity of operating conditions and bearing requirements continue to grow with the rapid advancement of technology. Therefore, it is necessary to study bearings carefully from many angles to select the best one from the thousands of types and sizes available. Usually, a bearing type is provisionally chosen considering the operating conditions, mounting arrangement, ease of mounting in the machine, allowable space, cost, availability, and other factors.

Then the size of the bearing is chosen to satisfy the desired life requirement. When doing this, in addition to fatigue life, it is necessary to consider grease life, noise and vibration, wear, and other factors. There is no fixed procedure for selecting bearings. It is good to investigate experience with similar applications and studies relevant to any special requirements for your specific application. When selecting bearings for new machines, unusual operating conditions, or harsh environments, please consult with NSK. The following diagram (Fig.2.1) shows an example of the bearing selection procedure.

Page number A19 A18, A37, A81 A19

Selection of bearing accuracy class Examination of internal clearance Page number Fitting A Difference in temperature between inner and outer rings A Speed A Misalignment of inner and outer rings A Amount of preloadA

Operating conditions A Magnitude and characteristics of loads A Temperature range A Materials, size, accuracies of shaft and housingA

Page number A82 A82, A83 A83 A84, A100

Determination of fitting

A95

A18 A98

Operating conditions and required performance Environmental conditions A Dimensions of shaft and housingA A

Determination of internal clearance Study of cage Speed Noise A Operating temperature A External vibration and shock A Rapid acceleration and deceleration A Moment load and misalignmentA A

Examination of special specifications Operating temperature Environment (seawater, vacuum, gases, chemicals, etc.) A Type of lubricationA A

Page number A57

Evaluation of bearing types

Allowable space A Magnitude and direction of loads A Vibration and shock A Operating speed, maximum speed A Misalignment of inner and outer rings A Fixing in axial direction and mounting arrangement A Ease of bearing mounting and dismounting A Sound and torque A Required rigidity A Availability and costA

Page number A18, A38 A18 A18 A18, A37 A18 A20 to A23 A19 A19 A19, A96 Examination of lubricating methods

Selection of cage type and material Page number A106, A107, A110, A112 A37 A105 A102 A123

Selection of special material, heat treatment for dimensional stability

Operating temperature range Speed A Lubricating methods A Type of seals A Maintenance and inspection intervalsA A

Determination of bearing type and mounting arrangement Page number A24, A25 A30, A32 -A32 A33

Selection of lubricating method, lubricant, and type of seals Examination of ease of mounting/ dismounting Procedure for mounting and dismounting A Necessary equipment A Dimensions affecting mountingA

Determination of bearing size

Expected life of machine A Dynamic and static equivalent loads A Speed A Permissible static load factor A Permissible axial loads (in the case of cylindrical roller bearings)A

Page number A116, A121 A116, A121 A100

Determination of bearing size

Determination of dimensions affecting mounting and procedure for mounting/ dismounting Final specifications for bearing and surrounding parts

Fig. 2.1 Flow Chart for Selection of Rolling Bearings

A 16

A 17

3. SELECTION OF BEARING TYPES3.1 Allowable Bearing SpaceThe allowable space for a rolling bearing and its adjacent parts is generally limited so the type and size of the bearing must be selected within such limits. In most cases, the shaft diameter is fixed first by the machine design; therefore, the bearing is often selected based on its bore size. For rolling bearings, there are numerous standardized dimension series and types, and the selection of the optimum bearing from among them is necessary. Fig. 3.1 shows the dimension series of radial bearings and corresponding bearing types.

3.3 Permissible Speed and Bearing TypesThe maximum speed of rolling bearings varies depending, not only the type of bearing, but also its size, type of cage, loads, lubricating method, heat dissipation, etc. Assuming the common oil bath lubrication method, the bearing types are roughly ranked from higher speed to lower as shown in Fig. 3.3.

Permissible bearing misalignment is given at the beginning of the dimensional tables for each bearing type.

3.5 Rigidity and Bearing TypesWhen loads are imposed on a rolling bearing, some elastic deformation occurs in the contact areas between the rolling elements and raceways. The rigidity of the bearing is determined by the ratio of bearing load to the amount of elastic deformation of the inner and outer rings and rolling elements. For the main spindles of machine tools, it is necessary to have high rigidity of the bearings together with the rest of the spindle. Consequently, since roller bearings are deformed less by load, they are more often selected than ball bearings. When extra high rigidity is required, bearings are given a preload, which means that they have a negative clearance. Angular contract ball bearings and tapered roller bearings are often preloaded.

3.4 Misalignment of Inner/Outer Rings and Bearing TypesBecause of deflection of a shaft caused by applied loads, dimensional error of the shaft and housing, and mounting errors, the inner and outer rings are slightly misaligned. The permissible misalignment varies depending on the bearing type and operating conditions, but usually it is a small angle less than 0.0012 radian (4'). When a large misalignment is expected, bearings having a self-aligning capability, such as self-aligning ball bearings, spherical roller bearings, and certain bearing units should be selected (Figs. 3.4 and 3.5).2 3 4 5 6

3.2 Load Capacity and Bearing TypesThe axial load carrying capacity of a bearing is closely related to the radial load capacity (see Page A24) in a manner that depends on the bearing design as shown in Fig. 3.2. This figure makes it clear that when bearings of the same dimension series are compared, roller bearings have a higher load capacity than ball bearings and are superior if shock loads exist.Width Series Diameter Series 2

3.6 Noise and Torque of Various Bearing TypesFig. 3.4 Permissible Misalignment of Spherical Roller Bearings

4 3 01 8908 09 00 01 02 03 04 18 19 10 29 20 22 23 39 30 31 32 33 48 49 40 41 59 50 69

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1

Since rolling bearings are manufactured with very high precision, noise and torque are minimal. For deep groove ball bearings and cylindrical roller bearings particularly, the noise level is sometimes specified depending on their purpose. For high precision miniature ball bearings, the starting torque is specified. Deep groove ball bearings are recommended for applications in which low noise and torque are required, such as motors and instruments.

Dimension Series Deep Groove Ball Bearings Angular Contact Ball Bearings Self-Aligning Ball Bearings Cylindrical Roller Bearings Spherical Roller Bearings Needle Roller Bearings Tapered Roller Bearings

3.7 Running Accuracy and Bearing TypesFor the main spindles of machine tools that require high running accuracy or high speed applications like superchargers, high precision bearings of Class 5, 4 or 2 are usually used. The running accuracy of rolling bearings is specified in various ways, and the specified accuracy classes vary depending on the bearing type. A comparison of the inner ring radial runout for the highest running accuracy specified for each bearing type is shown in Fig. 3.6. For applications requiring high running accuracy, deep groove ball bearings, angular contact ball bearings, and cylindrical roller bearings are most suitable.

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III II II II I II II II I II I II I II I I II

Fig. 3.5 Permissible Misalignment of Ball Bearing Units

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Fig. 3.1 Dimension Series of Radial BearingsBearing Types Bearing Type Single-Row Deep Groove Ball Bearings Single-Row Angular Contact Ball Bearings Cylindrical Roller(1) Bearings Tapered Roller Bearings Spherical Roller Bearings Note(1) The bearings with ribs can take some axial loads. Radial load capacity Axial load capacity1 2 3 4 1 2 3 4

Bearing Types Deep Groove Ball Bearings Angular Contact Ball Bearings Cylindrical Roller Bearings Needle Roller Bearings Tapered Roller Bearings Spherical Roller Bearings Thrust Ball Bearings Remarks

Relative permissible speed1 4 7 10 13

Highest accuracy specified Class 2 Class 2 Class 2 Class 4 Normal

Tolerance comparison of inner ring radial runout 1 2 3 4 5

Deep Groove Ball Bearings Angular Contact Ball Bearings Cylindrical Roller Bearings Tapered Roller Bearings Spherical Roller Bearings

3.8 Mounting and Dismounting of Various Bearing TypesSeparable types of bearings like cylindrical roller bearings, needle roller bearings and tapered roller bearings are convenient for mounting and dismounting. For machines in which bearings are mounted and dismounted rather often for periodic inspection, these types of bearings are recommended. Also, self-aligning ball bearings and spherical roller bearings (small ones) with tapered bores can be mounted and dismounted relatively easily using sleeves.

Oil bath lubrication With special measures to increase speed limit

Fig. 3.6 Relative Inner Ring Radial Runout of Highest Accuracy Class for Various Bearing Types

Fig. 3.2 Relative Load Capacities of Various Bearing Types

Fig. 3.3 Relative Permissible Speeds of Various Bearing Types

A 18

A 19

4. SELECTION OF BEARING ARRANGEMENTIn general, shafts are supported by only two bearings. When considering the bearing mounting arrangement, the following items must be investigated: (1) Expansion and contraction of the shaft caused by temperature variations. (2) Ease of bearing mounting and dismounting. (3) Misalignment of the inner and outer rings caused by deflection of the shaft or mounting error. (4) Rigidity of the entire system including bearings and preloading method. (5) Capability to sustain the loads at their proper positions and to transmit them. If measures to relieve a shafts thermal elongation and contraction are insufficient, abnormal axial loads are applied to the bearings, which can cause premature failure. For free-end bearings, cylindrical roller bearings or needle roller bearings with separable inner and outer rings that are free to move axially (NU, N types, etc.) are recommended. When these types are used, mounting and dismounting are also easier. When non-separable types are used as free-end bearings, usually the fit between the outer ring and housing is loose to allow axial movement of the running shaft together with the bearing. Sometimes, such elongation is relieved by a loose fitting between the inner ring and shaft. When the distance between the bearings is short and the influence of the shaft elongation and contraction is negligible, two opposed angular contact ball bearings or tapered roller bearings are used. The axial clearance (possible axial movement) after the mounting is adjusted using nuts or shims. The distinction between free-end and fixed-end bearings and some possible bearing mounting arrangements for various bearing types are shown in Fig. 4.1.

4.2 Example of Bearing ArrangementsSome representative bearing mounting arrangements considering preload and rigidity of the entire assembly, shaft elongation and contraction, mounting error, etc. are shown in Table 4.1.

Table 4. 1 Representative Bearing Mounting Arrangements and Application ExamplesBearing Arrangements Remarks Fixed-end Free-end Application Examples

4.1 Fixed-End and Free-End BearingsAmong the bearings on a shaft, only one can be a "fixed-end" bearing that is used to fix the shaft axially. For this fixed-end bearing, a type which can carry both radial and axial loads must be selected. Bearings other than the fixed-end one must be "freeend" bearings that carry only radial loads to relieve the shaft's thermal elongation and contraction.

fThis is a common arrangement in which abnormal loads are not applied to bearings even if the shaft expands or contracts. fIf the mounting error is small, this is suitable for high speeds.

Medium size electric motors, blowers

AFixed-end

BFree-end (separable bearing)

AFixed-end

CFree-end (non-separable bearing)

BEARING A Deep Groove Ball Bearing Matched Angular Contact Ball Bearing Double-Row Angular Contact Ball Bearing Self-Aligning Ball Bearing Cylindrical Roller Bearing with Ribs (NH, NUP types) Double-Row Tapered Roller Bearing Spherical Roller Bearing

BEARING B Cylindrical Roller Bearing (NU, N types) Needle Roller Bearing (NA type, etc.)

fThis can withstand heavy loads and shock loads and can take some axial load. fEvery type of cylindrical roller bearing is separable. This is helpful when interference is necessary for both the inner and outer rings.

Traction motors for rolling stock

D

D

No distinction between fixed-end and free-end

E

E

BEARING D,E(2) Angular Contact Ball Bearing Tapered Roller Bearing Magneto Bearing Cylindrical Roller Bearing (NJ, NF types)

BEARING C(1) Deep Groove Ball Bearing Matched Angular Contact Ball Bearing (back-toback) Double-Row Angular Contact Ball Bearing Self-Aligning Ball Bearing Double-Row Tapered Roller Bearing (KBE type) Spherical Roller Bearing

fThis is used when loads are relatively heavy. fFor maximum rigidity of the fixed-end bearing, it is a back-to-back type. fBoth the shaft and housing must have high accuracy and the mounting error must be small.

Table rollers for steel mills, main spindles of lathes

fThis is also suitable when interference is necessary for both the inner and outer rings. Heavy axial loads cannot be applied.

Calender rolls of paper making machines, axles of diesel locomotives

No distinction between fixed-end and free-end

BEARING F Deep Groove Ball Bearing Self-Aligning Ball Bearing Spherical Roller Bearing fThis is suitable for high speeds and heavy radial loads. Moderate axial loads can also be applied. fIt is necessary to provide some clearance between the outer ring of the deep groove ball bearing and the housing bore in order to avoid subjecting it to radial loads. Reduction gears in diesel locomotives

F

F

Notes: (1) In the figure, shaft elongation and contraction are relieved at the outside surface of the outer ring, but sometimes it is done at the bore. 2) For each type, two bearings are used in opposition. (

No distinction between fixed-end and free-end Fig. 4.1 Bearing Mounting Arrangements and Bearing TypesContinued on next page

A 20

A 21

SELECTION OF BEARING ARRANGEMENT

Table 4. 1 Representative Bearing Mounting Arrangements and Application Examples (cont'd)Bearing Arrangements Remarks Fixed-end Free-end Application Examples When there is no distinction between fixed-end and free-end Remarks Application Examples

fThis is the most common arrangement. fIt can sustain not only radial loads, but moderate axial loads also.

Double suction volute pumps, automotive transmissions

NJ + NJ mounting

fThis can withstand heavy loads and shock loads. fIt can be used if interference is necessary for both the inner and outer rings. fCare must be taken so the axial clearance doesn't become too small during running. fNF type + NF type mounting is also possible.

Final reduction gears of construction machines

fThis is the most suitable arrangement when there is mounting error or shaft deflection. fIt is often used for general and industrial applications in which heavy loads are applied.

Speed reducers, table rollers of steel mills, wheels for overhead travelling cranes

fSometimes a spring is used at the side of the outer ring of one bearing.

Small electric motors, small speed reducers, small pumps

fThis is suitable when there are rather heavy axial loads in both directions. fDouble row angular contact bearings may be used instead of a arrangement of two angular contact ball bearings.

Worm gear reducers

Vertical arrangements

Remarks

Application Examples

fMatched angular contact ball bearings are on the fixed end. fCylindrical roller bearing is on the free end. Application Examples

Vertical electric motors

When there is no distinction between fixed-end and free-end

Remarks

Back-to-back mounting

fThis arrangement is widely used since it can withstand heavy loads and shock loads. fThe back-to-back arrangement is especially good when the distance between bearings is short and moment loads are applied. fFace-to-face mounting makes mounting easier when interference is necessary for the inner ring. In general, this arrangement is good when there is mounting error. fTo use this arrangement with a preload, affection must be paid to the amount of preload and clearance adjustment.

Pinion shafts of automotive differential gears, automotive front and rear axles, worm gear reducers

Face-to-face mounting

fThe spherical center of the self-aligning seat must coincide with that of the self-aligning ball bearing. fThe upper bearing is on the free end.

Vertical openers (spinning and weaving machines)

Back-to-back mounting

fThis is used at high speeds when radial loads are not so heavy and axial loads are relatively heavy. fIt provides good rigidity of the shaft by preloading. fFor moment loads, back-to-back mounting is better than face-to-face mounting.

Grinding wheel shafts

Continued on next page

A 22

A 23

5. SELECTION OF BEARING SIZE5.1 Bearing LifeThe various functions required of rolling bearings vary according to the bearing application. These functions must be performed for a prolonged period. Even if bearings are properly mounted and correctly operated, they will eventually fail to perform satisfactorily due to an increase in noise and vibration, loss of running accuracy, deterioration of grease, or fatigue flaking of the rolling surfaces. Bearing life, in the broad sense of the term, is the period during which bearings continue to operate and to satisfy their required functions. This bearing life may be defined as noise life, abrasion life, grease life, or rolling fatigue life, depending on which one causes loss of bearing service. Aside from the failure of bearings to function due to natural deterioration, bearings may fail when conditions such as heat-seizure, fracture, scoring of the rings, damage of the seals or the cage, or other damage occurs. Conditions such as these should not be interpreted as normal bearing failure since they often occur as a result of errors in bearing selection, improper design or manufacture of the bearing surroundings, incorrect mounting, or insufficient maintenance. 5.1.1 Rolling Fatigue Life and Basic Rating Life When rolling bearings are operated under load, the raceways of their inner and outer rings and rolling elements are subjected to repeated cyclic stress. Because of metal fatigue of the rolling contact surfaces of the raceways and rolling elements, scaly particles may separate from the bearing material (Fig. 5.1). This phenomenon is called "flaking". Rolling fatigue life is represented by the total number of revolutions at which time the bearing surface will start flaking due to stress. This is called fatigue life. As shown in Fig. 5.2, even for seemingly identical bearings, which are of the same type, size, and material and receive the same heat treatment and other processing, the rolling fatigue life varies greatly even under identical operating conditions. This is because the flaking of materials due to fatigue is subject to many other variables. Consequently, "basic rating life", in which rolling fatigue life is treated as a statistical phenomenon, is used in preference to actual rolling fatigue life. Suppose a number of bearings of the same type are operated individually under the same conditions. After a certain period of time, 10% of them fail as a result of flaking caused by rolling fatigue. The total number of revolutions at this point is defined as the basic rating life or, if the speed is constant, the basic rating life is often expressed by the total number of operating hours completed when 10% of the bearings become inoperable due to flaking. In determining bearing life, basic rating life is often the only factor considered. However, other factors must also be taken into account. For example, the grease lifeA 24

of grease-prelubricated bearings (refer to Section 12, Lubrication, Page A107) can be estimated. Since noise life and abrasion life are judged according to individual standards for different applications, specific values for noise or abrasion life must be determined empirically.

Table 5. 1 Fatigue Life Factor f h for Various Bearing ApplicationsOperating Periods

Fatigue Life Factor f h ~3Small motors for home appliances like vacuum cleaners and washing machines Hand power tools

2~4Agricultural equipment

3~5

4~7

6~

5.2 Basic Load Rating and Fatigue Life5.2.1 Basic Load Rating The basic load rating is defined as the constant load applied on bearings with stationary outer rings that the inner rings can endure for a rating life of one million revolutions (106 rev). The basic load rating of radial bearings is defined as a central radial load of constant direction and magnitude, while the basic load rating of thrust bearings is defined as an axial load of constant magnitude in the same direction as the central axis. The load ratings are listed under C r for radial bearings and C a for thrust bearings in the dimension tables. 5.2.2 Machinery in which Bearings are Used and Projected Life It is not advisable to select bearings with unnecessarily high load ratings, for such bearings may be too large and uneconomical. In addition, the bearing life alone should not be the deciding factor in the selection of bearings. The strength, rigidity, and design of the shaft

Infrequently used or only for short periods

Used only occasionally but reliability is important

Used intermittently for relatively long periods

Rolling mill roll necks

Motors for home heaters and air conditioners Construction equipment Small motors Deck cranes General cargo cranes Pinion stands Passenger cars Escalators

Conveyors Elevator cable sheaves

Factory motors Machine tools Transmissions Vibrating screens Crushers

Crane sheaves Compressors Specialized transmissions Paper making machines

Used intermittently for more than eight hours daily

Centrifugal separators Air conditioning equipment Blowers Woodworking machines Large motors Axle boxes on railway rolling stock

Mine hoists Press flywheels Railway traction motors Locomotive axle boxes

Used continuously and high reliability is important

Waterworks Electric

pumps power stations Mine draining pumps

on which the bearings are to be mounted should also be considered. Bearings are used in a wide range of applications and the design life varies with specific applications and operating conditions. Table 5.1 gives an empirical fatigue life factor derived from customary operating experience for various machines. Also refer to Table 5.2. 5.2.3 Selection of Bearing Size Based on Basic Load Rating The following relation exists between bearing load and basic rating life: 3 For ball bearings L = C . . . . . . . . . . . . . . . . (5.1) P 10 For roller bearings L = C 3 . . . . . . . . . . . . . . (5.2) P where L : Basic rating life (106 rev) P : Bearing load (equivalent load) (N), {kgf} ..........(Refer to Page A30) C : Basic load rating (N), {kgf} For radial bearings, C is written C r For thrust bearings, C is written C a

By designating the basic rating life as L h (h), bearing speed as n (min1), fatigue life factor as f h, and speed factor as f n, the relations shown in Table 5.2 are obtained:

Table 5. 2 Basic Rating Life, Fatigue Life Factor and Speed FactorLife Parameters

Ball Bearings

Roller Bearings

Fig. 5.1 Example of Flaking

( ) ( )

Basic Rating Life Fatigue Life Factor

106 C 3= 106 C 500 fh3 L h= L h= 60n P 60n P

()

( ) =500 fP3 10

10 3

10 3 h

Rating Life

fh = fn CP

fh = fn C

Failure Probability

Average Life

Speed Factor

fn =

(

106 500 60n1 3

)

1 3

fn =

(

106 500 60n3

)

Life

Fig. 5.2 Failure Probability and Bearing Life

In the case of bearings that run at a constant speed, it is convenient to express the fatigue life in terms of hours. In general, the fatigue life of bearings used in automobiles and other vehicles is given in terms of mileage.

= (0.03n)-

= (0.03n)- 10

n, f n......Fig. 5.3 (See Page A26), Appendix Table 12(See Page C24) L h, f h....Fig. 5.4 (See Page A26), Appendix Table 13 (See Page C25)

A 25

SELECTION OF BEARING SIZE

n(min1)60000 40000 30000 20000 15000

fn0.08 0.09 0.1

n(min1)60000 40000 30000 20000 15000

fn0.105 0.11 0.12 0.13 0.14

Lh(h)80000 60000

fh5.5 5.0 4.5

Lh(h)80000 60000

fh4.5

4.0 40000 30000 4.0 40000 30000 3.5

If the bearing load P and speed n are known, determine a fatigue life factor f h appropriate for the projected life of the machine and then calculate the basic load rating C by means of the following equation. C=

5.2.5 Correction of Basic Rating Life As described previously, the basic equations for calculating the basic rating life are as follows:3 L 10 = C . . . . . . . . . . . . . . . . . (5.5) P 10 For roller bearings L 10 = C 3 . . . . . . . . . . . . . . . (5.6) P The L 10 life is defined as the basic rating life with a statistical reliability of 90%. Depending on the machines in which the bearings are used, sometimes a reliability higher than 90% may be required. However, recent improvements in bearing material have greatly extended the fatigue life. In addition, the developent of the Elasto-Hydrodynamic Theory of Lubrication proves that the thickness of the lubricating film in the contact zone between rings and rolling elements greatly influences bearing life. To reflect such improvements in the calculation of fatigue life, the basic rating life is adjusted using the following adjustment factors:

For ball bearings

0.12 0.14

0.15 0.16 0.17 0.18 0.19 0.20

fh P fn

. . . . . . . . . . . . . . . . . . . . . . . (5.3)

( ) ( )

10000 8000 6000 4000 3000 2000 1500 0.3 1000 800 600 0.4 400 300 200 150 100 80 60 50 40 30 20 15 10 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 0.6 0.7 0.5 0.25 0.16 0.18 0.20

10000 8000 6000

20000 15000

3.5

20000 15000

3.0

A bearing which satisfies this value of C should then be selected from the bearing tables. 5.2.4 Temperature Adjustment for Basic Load Rating If rolling bearings are used at high temperature, the hardness of the bearing steel decreases. Consequently, the basic load rating, which depends on the physical properties of the material, also decreases. Therefore, the basic load rating should be adjusted for the higher temperature using the following equation: C t = f t C . . . . . . . . . . . . . . . . . . . . . . . (5.4) where C t : Basic load rating after temperature correction (N), {kgf} f t : Temperature factor (See Table 5.3.) C : Basic load rating before temperature adjustment (N), {kgf} If large bearings are used at higher than 120 o C, they must be given special dimensional stability heat treatment to prevent excessive dimensional changes. The basic load rating of bearings given such special dimensional stability heat treatment may become lower than the basic load rating listed in the bearing tables.

4000 3000 2000 1500 1000 800 600 0.45 400 300 200 150 100 80 60 50 40 30 20 15 10 1.0 1.1 1.2 1.3 1.4 200 300 0.7 0.8 600 0.9 500 400 1000 800 0.5 2000 1500 0.35 0.40 4000 3000 0.25 10000 0.30 8000 6000

3.0 10000 2.5 8000 6000 2.0 2.0 1.9 1.8 1.7 1.6 1.5 2000 1500 3000 4000 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.3 1.2 1.1 1.0 0.95 0.90 0.85 0.80 0.75 200 1000 800 1.1 600 500 400 300 1.0 0.95 0.90 0.85 0.80 0.75 1.2 2.5

The life adjustment factor for operating conditions a 3 is used to adjust for various factors, particularly lubrication. If there is no misalignment between the inner and outer rings and the thickness of the lubricating film in the contact zones of the bearing is sufficient, it is possible for a 3 to be greater than one; however, a 3 is less than one in the following cases: When the viscosity of the lubricant in the contact zones between the raceways and rolling elements is low. When the circumferential speed of the rolling elements is very slow. When the bearing temperature is high. When the lubricant is contaminated by water or foreign matter. When misalignment of the inner and outer rings is excessive. It is difficult to determine the proper value for a 3 for specific operating conditions because there are still many unknowns. Since the special bearing property factor a 2 is also influenced by the operating conditions, there is a proposal to combine a 2 and a 3 into one quantity(a 2 a 3), and not consider them independently. In this case, under normal lubricating and operating conditions, the product (a 2 a 3) should be assumed equal to one. However, if the viscosity of the lubricant is too low, the value drops to as low as 0.2. If there is no misalignment and a lubricant with high viscosity is used so sufficient fluid-film thickness is secured, the product of (a 2 a 3) may be about two. When selecting a bearing based on the basic load rating, it is best to choose an a 1 reliability factor appropriate for the projected use and an empirically determined C/P or f h value derived from past results for lubrication, temperature, mounting conditions, etc. in similar machines. The basic rating life equations (5.1), (5.2), (5.5), and (5.6) give satisfactory results for a broad range of bearing loads. However, extra heavy loads may cause detrimental plastic deformation at ball/raceway contact points. When Pr exceeds C 0 r (Basic static load rating) or 0.5 C r, whichever is smaller, for radial bearings or Pa exceeds 0.5 C a for thrust bearings, please consult NSK to establish the applicablity of the rating fatigue life equations.

L na = a 1 a 2 a 3 L 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . (5.7)

0.6

1.4

Ball Bearings

Roller Bearings

Ball Bearings

Roller Bearings

Fig. 5.3 Bearing Speed and Speed Factor

Fig. 5.4 Fatigue Life Factor and Fatigue Life

where L na : Adjusted rating life in which reliability, material improvements, lubricating conditions, etc. are considered L 10 : Basic rating life with a reliability of 90% a 1 : Life adjustment factor for reliability a 2 : Life adjustment factor for special bearing properties a 3 : Life adjustment factor for operating conditions The life adjustment factor for reliability, a 1, is listed in Table 5.4 for reliabilities higher than 90%. The life adjustment factor for special bearing properties, a 2, is used to reflect improvements in bearing steel. NSK now uses vacuum degassed bearing steel, and the results of tests by NSK show that life is greatly improved when compared with earlier materials. The basic load ratings C r and C a listed in the bearing tables were calculated considering the extended life achieved by improvements in materials and manufacturing techniques. Consequently, when estimating life using Equation (5.7), it is sufficient to assume that is greater than one.

Table 5.3 Temperature Factor f tBearing Temperature oC Temperature Factor f t 125 1.00 150 1.00 175 0.95 200 0.90 250 0.75 Reliability (%)

Table 5.4 Reliability Factor a 190 1.00 95 0.62 96 0.53 97 0.44 98 0.33 99 0.21

a1

A 26

A 27


5.3 Calculation of Bearing LoadsThe loads applied on bearings generally include the weight of the body to be supported by the bearings, the weight of the revolving elements themselves, the transmission power of gears and belting, the load produced by the operation of the machine in which the bearings are used, etc. These loads can be theoretically calculated, but some of them are difficult to estimate. Therefore, it becomes necessary to correct the estimated using empirically derived data. 5.3.1 Load Factor When a radial or axial load has been mathematically calculated, the actual load on the bearing may be greater than the calculated load because of vibration and shock present during operation of the machine. The actual load may be calculated using the following equation: Fr = fw Frc Fa = fw Fac

5.3.2 Bearing Loads in Belt or Chain Transmission Applications The force acting on the pulley or sprocket wheel when power is transmitted by a belt or chain is calculated using the following equations. M = 9 550 000H / n ....( N m m ) .............(5.9) = 0 974 000H / n ....{kgfmm}

5.3.3 Bearing Loads in Gear Transmission Applications The loads imposed on gears in gear transmissions vary according to the type of gears used. In the simplest case of spur gears, the load is calculated as follows: M = 9 550 000H / n ....( N m m ) ...........(5.12) = 0 974 000H / n ....{kgf mm}

5.3.4 Load Distribution on Bearings In the simple examples shown in Figs. 5.5 and 5.6. The radial loads on bearings1and 2 can be calculated using the following equations: FC1= b K ...............................................(5.16)

}

c

}

FC2= a K ..............................................(5.17)

c

Pk = M / r .............................................(5.10) where M : Torque acting on pulley or sprocket wheel (N mm), {kgf mm} Pk : Effective force transmitted by belt or chain (N), {kgf} H : Power transmitted(kW)

Pk = M / r .............................................(5.13) Sk = Pk tan ...........................................(5.14) Kc = P k2+S k2 = Pk sec .........................(5.15) where M : Torque applied to gear (N . mm),{kgf . mm} Pk : Tangential force on gear (N), {kgf} Sk : Radial force on gear (N), {kgf} Kc : Combined force imposed on gear (N), {kgf} H : Power transmitted (kW)

where

FC1 : Radial load applied on bearing1 (N), {kgf} FC2 : Radial load applied on bearing2 (N), {kgf} K : Shaft load (N), {kgf}

} . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (5.8)

n : Speed (min1) r : Effective radius of pulley or sprocketwheel (mm) When calculating the load on a pulley shaft, the belt tension must be included. Thus, to calculate the actual load Kb in the case of a belt transmission, the effective transmitting power is multiplied by the belt factor f b, which represents the belt tension. The values of the belt factor f b for different types of belts are shown in Table 5.6. Kb = f b Pk .........................................(5.11) In the case of a chain transmission, the values corresponding to f b should be 1.25 to 1.5.

When these loads are applied simultaneously, first the radial load for each should be obtained, and then, the sum of the vectors may be calculated according to the load direction.

where Fr, Fa : Loads applied on bearing (N), {kgf} Frc, Fac : Theoretically calculated load (N) , {kgf}

n : Speed (min1) r : Pitch circle radius of drive gear (mm) : Pressure angleIn addition to the theoretical load calculated above, vibration and shock (which depend on how accurately the gear is finished) should be included using the gear factor f g by multiplying the theoretically calculated load by this factor. The values of f g should generally be those in Table 5.7. When vibration from other sources accompanies gear operation, the actual load is obtained by multiplying the load factor by this gear factor.

c a b FC1 FC1 FC2Bearing1

a c b

fw : Load factorThe values given in Table 5.5 are usually used for the load factor fw.

Bearing1 K Bearing 2

K FC2 Bearing 2

Fig. 5.5 Radial Load Distribution (1)

Fig. 5.6 Radial Load Distribution (2)

Table 5. 5 Values of Load Factor fwOperating Conditions Smooth operation free from shocks Normal operation Typical Applications Electric motors, Machine tools, Air conditioners Air blowers, Compressors, Elevators, Cranes, Paper making machines Construction equipment, Crushers, Vibrating screens, Rolling mills

Table 5. 6 Belt Factor f b

fw1.0 to 1.2 Toothed belts V belts 1.2 to 1.5

Type of Belt

fb1.3 to 2.0 2.0 to 2.5 2.5 to 3.0 4.0 to 5.0

Table 5. 7 Values of Gear Factor f gGear Finish Accuracy Precision ground gears Ordinary machined gears

5.3.5 Average of Fluctuating Load When the load applied on bearings fluctuates, an average load which will yield the same bearing life as the fluctuating load should be calculated. (1) When the relation between load and rotating speed is divided into the following steps (Fig. 5.7) Load F1 : Speed n1 ; Operating time t1 Load F2 : Speed n2 ; Operating time t2

fg1.0~1.1 1.1~1.3

Flat belts with tension pulley Flat belts

Load Fn : Speed nn ; Operating time tn Then, the average load Fm may be calculated using the following equation: Fm =p

Operation accompanied by shock and vibration

1.5 to 3.0

n + + ... F n tt + F tn+t.........+ F tn t n +n1 p 1 1 2 p 2 2

n

p

n n

1 1

2 2

n n

..........................(5.18)

where Fm : Average fluctuating load (N), {kgf} p = 3 for ball bearings p = 10/3 for roller bearingsA 28 A 29


The average speed nm may be calculated as follows: ... 2+ nm = n1t1 + n2t.........+ nntn ........................(5.19) t1 + t2 + + tn (2) When the load fluctuates almost linearly (Fig. 5.8), the average load may be calculated as follows: 1 FmH (Fmin + 2Fmax) ..........................(5.20) 3 where Fmin : Minimum value of fluctuating load (N), {kgf} Fmax : Maximum value of fluctuating load (N), {kgf}

5.4 Equivalent LoadIn some cases, the loads applied on bearings are purely radial or axial loads; however, in most cases, the loads are a combination of both. In addition, such loads usually fluctuate in both magnitude and direction. In such cases, the loads actually applied on bearings cannot be used for bearing life calculations; therefore, a hypothetical load that has a constant magnitude and passes through the center of the bearing, and will give the same bearing life that the bearing would attain under actual conditions of load and rotation should be estimated. Such a hypothetical load is called the equivalent load.

(3) When the load fluctuation is similar to a sine wave (Fig. 5.9), an approximate value for the average load F m may be calculated from the following equation: In the case of Fig. 5.9 (a) FmH0.65 Fmax ........................................(5.21) In the case of Fig. 5.9 (b) FmH0.75 Fmax ........................................(5.22)(4) When both a rotating load and a stationary load are applied (Fig. 5.10). FR : Rotating load (N), {kgf} FS : Stationary load (N), {kgf} An approximate value for the average load Fm may be calculated as follows: a) Where FRFS F2 FmHFR + 0.3FS + 0.2 S ..........................(5.23) FR b) Where FReX = 0.56 Y = 1.67 (the value of Y is obtained by linear interpolation) Therefore, the dynamic equivalent load P is P = XFr + YFa = 0.56 2 500 + 1.67 1 000 = 3 070N, {313kgf} C r 29 100 = = 9.48 3 070 P fh = fn C r = 0.333 29 100 = 3.16 3 070 P

fh = fn C r = 0.333 29 100 = 3.88

fh = fn C r = 0.444 P

Cr 3.45 62 600

consequently, C r490 000N, {50 000kgf} Among spherical roller bearings of series 231 satisfying this value of C r, the smallest is 23126CE4 (C r = 505 000N, {51 500kgf}) Once the bearing is determined, substitude the value of Y3 in the equation and obtain the value of P. P = Fr + Y3 Fa = 45 000 + 2.4 8 000 = 64 200N, {6 550kgf} Lh = 500 ( fn Cr ) P10 3

To distribute the radial load Fr on bearings1and2, the effective load centers must be located for tapered roller bearings. Obtain the effective load center a for bearings 1and 2 from the bearing table, then obtain the relative position of the radial load Fr and effective load centers. The result will be as shown in Fig. 5.14. Consequently, the radial load applied on bearings1(HR30305DJ) and 2 (HR30206J) can be obtained from the following equations: Fr1= 5 500 23.9 = 1 569N, {160kgf} 83.8 59.9 Fr2 = 5 500 = 3 931N, {401kgf} 83.8

From the data in the bearing table, the following values are obtained;Basic dynamic load rating Axial load factor Constant

This value of fh corresponds approximately to 15 800 hours for ball bearings. (Example 4) Select a spherical roller bearing of series 231 satisfying the following conditions: Radial load Fr = 45 000N, {4 950kgf} Axial load Fa = 8 000N, {816kgf} Speed n = 500min1 Basic rating life Lh30 000h The value of the fatigue life factor f h which makes Lh30 000h is bigger than 3.45 from Fig. 5.4 (Page A26).

= 500 (0.444 10

505 000 ) 64 200

10 3

Bearings

Cr(N) {kgf}{3 900} {4 400}

Y1Y1 = 0.73 Y2 = 1.60

e0.83 0.38

= 500 3.49 3 H32 000h (Example 5) Assume that tapered roller bearings HR30305DJ and HR30206J are used in a back-to-back arrangement as shown in Fig. 5.14, and the distance between the cup back faces is 50mm. Calculate the basic rating life of each bearing when beside the radial load Fr = 5 500N, {561kgf}, axial load Fae =2 000N,{204kgf} are applied to HR30305DJ as shown in Fig. 5.14. The speed is 600min1.

Bearing1(HR30305DJ) Bearing2(HR30206J)

38 000 43 000

fh = fn C r = 0.26 P therefore, C r2.72

Cr 2.72 3 000

3 000 = 31 380N, {3 200kgf} 0.26 Among the data listed in the bearing table on Page B12, 6210 should be selected as one that satisfies the above conditions.

When radial loads are applied on tapered roller bearings, an axial load component is produced, which must be considered to obtain the dynamic equivalent radial load (Refer to Paragraph 5.4.2, Page A31).

A 34

A 35


6. LIMITING SPEEDFae + 0.6 Fr2 = 2 000 + 0.6 3 931 Y2 1.6 = 3 474N, {354kgf} 0.6 F = 0.6 1 569 = 1 290N, {132kgf} Y1 r1 0.73 Therefore, with this bearing arrangement, the axial load 0.6 F is applied on bearing1 but not on Fae + Y2 r 2 bearing 2. For bearing1 Fr1= 1 569N, {160kgf} Fa1= 3 474N, {354kgf} since Fa1 / Fr1= 2.2>e = 0.83 the dynamic equivalent load P1= XFr1+ Y1Fa1 = 0.4 1 569 + 0.73 3 474 = 3 164N, {323kgf} C The fatigue life factor f h = fn r P1 0.42 38 000 = = 5.04 3 164 and the rating fatigue life L h = 500 5.04 3 = 109 750h For bearing 2 since Fr2 = 3 931N, {401kgf}, Fa2 = 0 the dynamic equivalent load P2 = Fr2 = 3 931N, {401kgf} the fatigue life factor 3 931 10 and the rating fatigue life Lh = 500 4.59 3 = 80 400h are obtained. Remarks For face-to-face arrangements (DF type), please contact NSK. (Example 6) Select a bearing for a speed reducer under the following conditions: Operating conditions Radial load Fr = 245 000 N, {25 000kgf} Axial load Fa = 49 000N, {5 000kgf} n = 500min1 Speed Size limitation Shaft diameter: 300mm Bore of housing: Less than 500mm10

In this application, heavy loads, shocks, and shaft deflection are expected; therefore, spherical roller bearings are appropriate. The following spherical roller bearings satisfy the above size limitation (refer to Page B192)Basic dynamic load rating Constant Factor

d

D

B

Bearing No.

Cr(N) {kgf}

e

Y3

300 420 90 23960 CAE4 1 230 000 460 118 23060 CAE4 1 920 000 460 160 24060 CAE4 2 310 000 500 160 23160 CAE4 2 670 000 500 200 24160 CAE4 3 100 000

125 000 0.19 3.5 196 000 0.24 2.8 235 000 0.32 2.1 273 000 0.31 2.2 315 000 0.38 1.8

since Fa / Fr = 0.20e Fr X 0.56 0.56 0.56 0.56 0.56 0.56 0.56 0.56 0.56 Y 2.30 1.99 1.71 1.55 1.45 1.31 1.15 1.04 1.00

jD 1

Open Type

Shielded Type ZZ

Non-Contact Sealed Type VV Factor{kgf}

Contact Sealed Type DD DDU

With Snap Ring Groove N

With Snap Ring NR Bearing NumbersOpen Shielded Sealed

CY

Static Equivalent Load Fa >0.8, P0 =0.6Fr +0.5Fa Fr Fa 0.8, P0 =Fr Fr Abutment and Fillet Dimensions(mm)

Boundary Dimensions(mm)

Basic Load Ratings(N)

Limiting Speeds (min 1)Grease OilOpen Z Open Z ZZ V VV

Snap Ring Groove Dimensions (1) With With Snap Snap Ring Ring Groove N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR(mm)

Snap Ring (1) Dimensions

Mass(kg)

d50

D65 72 80 80 90 110 72 80 90 90 100 120 78 85 95 95 110 130 85 90 100 100 120 140 90 100 110 110 125 150 95 105 115 115 130 160

B7 12 10 16 20 27 9 13 11 18 21 29 10 13 11 18 22 31 10 13 11 18 23 33 10 16 13 20 24 35 10 16 13 20 25 37

rmin

Cr6 400 14 500 15 400 21 800 35 000 62 000 8 800 16 000 19 400 28 300 43 500 71 500 11 500 19 400 20 000 29 500 52 500 82 000 11 900 17 400 20 500 30 500 57 500 92 500 12 100 23 700 26 800 38 000 62 000 104 000 12 500 24 400 27 600 39 500 66 000 113 000

C 0r6 200 11 700 12 400 16 600 23 200 38 500 8 500 13 300 16 300 21 200 29 300 44 500 10 900 16 300 17 500 23 200 36 000 52 000 12 100 16 100 18 700 25 200 40 000 60 000 12 700 21 200 23 600 31 000 44 000 68 000 13 900 22 600 25 300 33 500 49 500 77 000

Cr655 1 480 1 570 2 220 3 600 6 300 900 1 630 1 980 2 880 4 450 7 300 1 170 1 980 2 040 3 000 5 350 8 350 1 220 1 770 2 090 3 100 5 850 9 450 1 230 2 420 2 730 3 900 6 350 10 600 1 280 2 480 2 820 4 050 6 750 11 600

C 0r635 1 200 1 260 1 700 2 370 3 900 865 1 350 1 660 2 170 2 980 4 550 1 120 1 660 1 780 2 370 3 700 5 300 1 230 1 640 1 910 2 570 4 100 6 100 1 300 2 160 2 410 3 150 4 500 6 950 1 410 2 300 2 580 3 400 5 050 7 850

f017.2 16.1 16.1 15.6 14.4 13.2 17.0 16.2 16.2 15.3 14.3 13.1 16.9 16.2 16.3 15.6 14.3 13.1 17.0 16.6 16.5 15.8 14.4 13.2 17.2 16.3 16.3 15.6 14.5 13.2 17.3 16.5 16.4 15.8 14.7 13.2

DU DDU

amax

bmin

D1max

r0max

rNmin

D2

(mm)

fmin

d a( )2

D a( )2

ramax

Dxmin

CYmax approx

max

max

max

max

55

60

65

70

75

0.3 0.6 0.6 1 1.1 2 0.3 1 0.6 1.1 1.5 2 0.3 1 0.6 1.1 1.5 2.1 0.6 1 0.6 1.1 1.5 2.1 0.6 1 0.6 1.1 1.5 2.1 0.6 1 0.6 1.1 1.5 2.1

9 500 9 000 8 500 8 500 7 100 6 000 8 500 8 000 7 500 7 500 6 300 5 600 8 000 7 500 7 100 7 100 5 600 5 300 7 500 7 100 6 700 6 700 5 300 4 800 6 700 6 300 6 000 6 000 5 000 4 500 6 300 6 000 5 600 5 600 4 800 4 300

5 300 5 300 4 800 4 800 4 300 4 800 4 500 4 500 4 300 4 000 4 500 4 300 4 000 3 800 3 600 4 000 4 000 4 000 3 600 3 400 3 800 3 600 3 600 3 400 3 200 3 600 3 400 3 400 3 200 2 800

11 000 11 000 10 000 10 000 8 500 7 500 10 000 9 500 9 000 9 000 7 500 6 700 9 500 9 000 8 500 8 500 7 100 6 300 8 500 8 500 8 000 8 000 6 300 6 000 8 000 7 500 7 100 7 100 6 300 5 300 7 500 7 100 6 700 6 700 5 600 5 000

6810 6910 16010 6010 6210 6310 6811 6911 16011 6011 6211 6311 6812 6912 16012 6012 6212 6312 6813 6913 16013 6013 6213 6313 6814 6914 16014 6014 6214 6314 6815 6915 16015 6015 6215 6315

ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ

VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV

DDU DDU DDU DDU DDU DDU DDU DDU DDU DDU DD DDU DDU DDU DDU DD DDU DDU DDU DDU DD DDU DDU DDU DDU DDU DDU DDU DDU DDU

1.30 1.70 2.49 3.28 3.28 1.70 2.10 2.87 3.28 4.06 1.70 2.10 2.87 3.28 4.06 1.70 2.10 2.87 4.06 4.90 1.70 2.50 2.87 4.06 4.90 1.70 2.50 2.87 4.06 4.90

0.95 0.95 1.90 2.70 2.70 0.95 1.30 2.70 2.70 3.10 1.30 1.30 2.70 2.70 3.10 1.30 1.30 2.70 3.10 3.10 1.30 1.30 2.70 3.10 3.10 1.30 1.30 2.70 3.10 3.10

63.7 70.7 076.81 086.79 106.81 70.7 77.9 086.79 96.8 115.21 76.2 82.9 091.82 106.81 125.22 82.9 87.9 96.8 115.21 135.23 87.9 97.9 106.81 120.22 145.24 92.9 102.60 111.81 125.22 155.22

0.25 0.25 0.60 0.60 0.60 0.25 0.40 0.60 0.60 0.60 0.40 0.40 0.60 0.60 0.60 0.40 0.40 0.60 0.60 0.60 0.40 0.40 0.60 0.60 0.60 0.40 0.40 0.60 0.60 0.60

0.3 0.5 0.5 0.5 0.5 0.3 0.5 0.5 0.5 0.5 0.3 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

067.8 074.8 086.6 096.5 116.6 074.8 084.4 096.5 106.5 129.7 082.7 089.4 101.6 116.6 139.7 089.4 094.4 106.5 129.7 149.7 094.4 104.4 116.6 134.7 159.7 099.4 110.7 121.6 139.7 169.7

0.85 0.85 1.70 2.46 2.46 0.85 1.12 2.46 2.46 2.82 1.12 1.12 2.46 2.46 2.82 1.12 1.12 2.46 2.82 2.82 1.12 1.12 2.46 2.82 2.82 1.12 1.12 2.46 2.82 2.82

52 54 54 55 56.5 59 57 60 59 61.5 63 64 62 65 64 66.5 68 71 69 70 69 71.5 73 76 74 75 74 76.5 78 81 79 80 79 81.5 83 86

52.5 55 58.5 60 68 59 61.5 64 66.5 72.5 64 66 69 74.5 79 69 71.5 73 80 85.5 74.5 77.5 80.5 84 92 79.5 82 85.5 90 98.5

63 68 76 75 83.5 101 70 75 86 83.5 92 111 76 80 91 88.5 102 119 81 85 96 93.5 112 129 86 95 106 103.5 117 139 91 100 111 108.5 122 149

0.3 0.6 0.6 1 1 2 0.3 1 0.6 1 1.5 2 0.3 1 0.6 1 1.5 2 0.6 1 0.6 1 1.5 2 0.6 1 0.6 1 1.5 2 0.6 1 0.6 1 1.5 2

68.5 76 88 98 118 76 86 98 108 131.5 84 91 103 118 141.5 91 96 108 131.5 152 96 106 118 136.5 162 101 112 123 141.5 172

1.8 2.3 3.8 5.4 5.4 2.3 2.9 5.0 5.4 6.5 2.5 2.9 5.0 5.4 6.5 2.5 2.9 5.0 6.5 7.3 2.5 3.3 5.0 6.5 7.3 2.5 3.3 5.0 6.5 7.3

0.050 0.135 0.175 0.261 0.459 1.06 0.081 0.189 0.257 0.381 0.619 1.37 0.103 0.192 0.281 0.412 0.783 1.72 0.128 0.218 0.30 0.439 1.0 2.11 0.134 0.349 0.441 0.608 1.09 2.57 0.149 0.364 0.463 0.649 1.19 3.08

Notes (1) For tolerances for the snap ring grooves and snap ring dimensions, refer to Pages A50 to A53. (2) When heavy axial loads are applied, increase da and decrease Da from the above values.

Remarks 1. Diameter Series 7 (extra thin section bearings) are also available, please contact NSK. 2. When using bearings with rotating outer rings, contact NSK if they are sealed, shielded, or have snap rings.

B 12

B 13

SINGLE-ROW DEEP GROOVE BALL BEARINGSBore DiameterB r r jD jd jD 2 jDa

80 105 mmf rN a b r0 ra ra jda jD X ra

Dynamic Equivalent Load P =X Fr +Y Fa f 0Fa

C 0r0.172 0.345 0.689 1.03 1.38 2.07 3.45 5.17 6.89

e0.19 0.22 0.26 0.28 0.30 0.34 0.38 0.42 0.44 X 1 1 1 1 1 1 1 1 1

Fa e Fr Y 0 0 0 0 0 0 0 0 0

Fa >e Fr X 0.56 0.56 0.56 0.56 0.56 0.56 0.56 0.56 0.56 Y 2.30 1.99 1.71 1.55 1.45 1.31 1.15 1.04 1.00

jD 1

Open Type

Shielded Type ZZ





CY





Snap Ring Groove Dimensions (1) With With Snap Snap Ring Ring Groove N N N N N N N N N N N N N N N N N N N N N N N N N N N N NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR (mm)


Mass(kg)

d80

D100 110 125 125 140 170 110 120 130 130 150 180 115 125 140 140 160 190 120 130 145 145 170 200 125 140 150 150 180 215 130 145 160 160 190 225

B10 16 14 22 26 39 13 18 14 22 28 41 13 18 16 24 30 43 13 18 16 24 32 45 13 20 16 24 34 47 13 20 18 26 36 49

rmin

Cr12 700 25 000 32 000 47 500 72 500 123 000 18 700 32 000 33 000 49 500 84 000 133 000 19 000 33 000 41 500 58 000 96 000 143 000 19 300 33 500 43 000 60 500 109 000 153 000 19 600 43 000 42 500 60 000 122 000 173 000 19 800 42 500 52 000 72 500 133 000 184 000

C 0r14 500 24 000 29 600 40 000 53 000 86 500 20 000 29 600 31 500 43 000 62 000 97 000 21 000 31 500 39 500 50 000 71 500 107 000 22 000 33 500 42 000 54 000 82 000 119 000 23 000 42 000 42 000 54 000 93 000 141 000 23 900 42 000 50 500 66 000 105 000 154 000

Cr1 290 2 540 3 250 4 850 7 400 12 500 1 910 3 250 3 350 5 050 8 550 13 500 1 940 3 350 4 250 5 950 9 800 14 500 1 970 3 450 4 350 6 150 11 100 15 600 2 000 4 350 4 300 6 150 12 500 17 700 2 020 4 300 5 300 7 400 13 600 18 700

C 0r1 470 2 450 3 000 4 050 5 400 8 850 2 040 3 000 3 200 4 400 6 300 9 850 2 140 3 200 4 000 5 050 7 300 11 000 2 240 3 400 4 250 5 500 8 350 12 100 2 340 4 250 4 300 5 550 9 500 14 400 2 440 4 300 5 150 6 700 10 700 15 700

f017.4 16.6 16.4 15.6 14.6 13.3 17.1 16.4 16.5 15.8 14.5 13.3 17.2 16.5 16.3 15.6 14.5 13.3 17.2 16.6 16.4 15.8 14.4 13.3 17.3 16.4 16.5 15.9 14.4 13.2 17.4 16.5 16.3 15.8 14.4 13.2

DU DDU

amax

bmin

D1max

r0max

rNmin

D2

(mm)

fmin

d a( )2

D a( )2

ramax

Dxmin

CYmax approx

max

max

max

max

85

90

95

100

105

0.6 1 0.6 1.1 2 2.1 1 1.1 0.6 1.1 2 3 1 1.1 1 1.5 2 3 1 1.1 1 1.5 2.1 3 1 1.1 1 1.5 2.1 3 1 1.1 1 2 2.1 3

6 000 5 600 5 300 5 300 4 500 4 000 5 600 5 300 5 000 5 000 4 300 3 800 5 300 5 000 4 800 4 800 4 000 3 600 5 000 4 800 4 500 4 500 3 800 3 000 4 800 4 500 4 300 4 300 3 600 2 800 4 800 4 300 4 000 4 000 3 400 2 600

3 400 3 200 3 200 3 000 2 800 3 200 3 000 3 000 2 800 2 600 3 000 2 800 2 800 2 600 2 400 2 800 2 800 2 600 2 600 2 400 2 800 2 600 2 600 2 400 2 200 2 600 2 400 2 200 2 000

7 100 6 700 6 300 6 300 5 300 4 800 6 700 6 300 6 000 6 000 5 000 4 500 6 300 6 000 5 600 5 600 4 800 4 300 6 000 5 600 5 300 5 300 4 500 3 600 5 600 5 300 5 300 5 300 4 300 3 400 5 600 5 300 4 800 4 800 4 000 3 200

6816 6916 16016 6016 6216 6316 6817 6917 16017 6017 6217 6317 6818 6918 16018 6018 6218 6318 6819 6919 16019 6019 6219 6319 6820 6920 16020 6020 6220 6320 6821 6921 16021 6021 6221 6321

ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ

VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV VV

DDU DDU DDU DDU DDU DDU DDU DDU DDU DDU DDU DDU DDU DDU DDU DD DDU DDU DDU DDU DD DDU DDU DDU DDU DDU DDU DDU DDU

1.70 2.50 2.87 4.90 5.69 2.10 3.30 2.87 4.90 5.69 2.10 3.30 3.71 4.90 5.69 2.10 3.30 3.71 5.69 5.69 2.10 3.30 3.71 5.69 2.10 3.30 3.71 5.69

1.3 1.3 3.1 3.1 3.5 1.3 1.3 3.1 3.1 3.5 1.3 1.3 3.1 3.1 3.5 1.3 1.3 3.1 3.5 3.5 1.3 1.9 3.1 3.5 1.3 1.9 3.1 3.5

97.9 107.60 120.22 135.23 163.65 107.60 117.60 125.22 145.24 173.66 112.60 122.60 135.23 155.22 183.64 117.60 127.60 140.23 163.65 193.65 122.60 137.60 145.24 173.66 127.60 142.60 155.22 183.64

0.4 0.4 0.6 0.6 0.6 0.4 0.4 0.6 0.6 0.6 0.4 0.4 0.6 0.6 0.6 0.4 0.4 0.6 0.6 0.6 0.4 0.6 0.6 0.6 0.4 0.6 0.6 0.6

0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

104.4 115.7 134.7 149.7 182.9 115.7 125.7 139.7 159.7 192.9 120.7 130.7 149.7 169.7 202.9 125.7 135.7 154.7 182.9 212.9 130.7 145.7 159.7 192.9 135.7 150.7 169.7 202.9

1.12 1.12 2.82 2.82 3.10 1.12 1.12 2.82 2.82 3.10 1.12 1.12 2.82 2.82 3.10 1.12 1.12 2.82 3.10 3.10 1.12 1.70 2.82 3.10 1.12 1.70 2.82 3.10

84 85 84 86.5 89 91 90 91.5 89 91.5 94 98 95 96.5 95 98 99 103 100 101.5 100 103 106 108 105 106.5 105 108 111 113 110 111.5 110 114 116 118

84.5 87.5 91 95.5 104.5 90.5 94.5 96 102 110.5 95.5 98.5 103 107.5 117 101.5 103.5 108.5 114 123.5 105.5 111 112.5 121.5 133 110.5 116 120 127.5 138

96 105 121 118.5 131 159 105 113.5 126 123.5 141 167 110 118.5 135 132 151 177 115 123.5 140 137 159 187 120 133.5 145 142 169 202 125 138.5 155 151 179 212

0.6 1 0.6 1 2 2 1 1 0.6 1 2 2.5 1 1 1 1.5 2 2.5 1 1 1 1.5 2 2.5 1 1 1 1.5 2 2.5 1 1 1 2 2 2.5

106 117 136.5 152 185 117 127 141.5 162 195 122 132 152 172 205 127 137 157 185 215 132 147 162 195 137 152 172 205

2.5 3.3 5.3 7.3 8.4 2.9 4.1 5.3 7.3 8.4 2.9 4.1 6.1 7.3 8.4 2.9 4.1 6.1 8.4 8.4 2.9 4.7 6.1 8.4 2.9 4.7 6.1 8.4

0.151 0.391 0.621 0.872 1.42 3.67 0.263 0.55 0.652 0.918 1.76 4.28 0.276 0.585 0.873 1.19 2.18 4.98 0.297 0.601 0.904 1.23 2.64 5.76 0.31 0.828 0.945 1.29 3.17 7.04 0.324 0.856 1.24 1.58 3.79 8.09


Remarks 1. Diameter Series 7 (extra thin section bearings) are also available, please contact NSK. 2. When using bearings with rotating outer rings, contact NSK if they are sealed, shielded, or have snap rings.

B 14

B 15

SINGLE-ROW DEEP GROOVE BALL BEARINGSBore DiameterB r r jD jd jD 2 jDa

110 160 mmf rN a b r0 ra ra jda jD X ra


C 0r0.172 0.345 0.689 1.03 1.38 2.07 3.45 5.17 6.89

e0.19 0.22 0.26 0.28 0.30 0.34 0.38 0.42 0.44 X 1 1 1 1 1 1 1 1 1

Fa e Fr Y 0 0 0 0 0 0 0 0 0

Fa >e Fr X 0.56 0.56 0.56 0.56 0.56 0.56 0.56 0.56 0.56 Y 2.30 1.99 1.71 1.55 1.45 1.31 1.15 1.04 1.00

jD 1

Open Type

Shielded Type ZZ ZZS





CY





Snap Ring Groove Dimensions (1) With With Snap Snap Ring Ring Groove N N N N N N N N N N N N N N NR NR NR NR NR NR NR NR NR NR NR NR NR NR (mm)


Mass(kg)

d110

D140 150 170 170 200 240 150 165 180 180 215 260 165 180 200 200 230 280 175 190 210 210 250 300 190 210 225 225 270 320 200 220 240 240 290 340

B16 20 19 28 38 50 16 22 19 28 40 55 18 24 22 33 40 58 18 24 22 33 42 62 20 28 24 35 45 65 20 28 25 38 48 68

rmin

Cr28 100 43 500 57 500 85 000 144 000 205 000 28 900 53 000 56 500 88 000 155 000 207 000 37 000 65 000 75 500 106 000 167 000 229 000 38 500 66 500 77 500 110 000 166 000 253 000 47 500 85 000 84 000 126 000 176 000 274 000 48 500 87 000 99 000 137 000 185 000 278 000

C 0r32 500 44 500 56 500 73 000 117 000 179 000 35 500 54 000 57 500 80 000 131 000 185 000 44 000 67 500 77 500 101 000 146 000 214 000 48 000 72 000 82 500 109 000 150 000 246 000 58 500 90 500 91 000 126 000 168 000 284 000 61 000 96 000 108 000 135 000 186 000 287 000

Cr2 860 4 450 5 850 8 650 14 700 20 900 2 950 5 400 5 800 9 000 15 800 21 100 3 750 6 650 7 700 10 800 17 000 23 400 3 900 6 800 7 900 11 200 17 000 25 800 4 850 8 650 8 550 12 800 18 000 28 000 4 950 8 850 10 100 13 900 18 900 28 300

C 0r3 350 4 550 5 800 7 450 11 900 18 300 3 650 5 500 5 850 8 150 13 400 18 800 4 450 6 850 7 900 10 300 14 900 21 800 4 850 7 300 8 400 11 100 15 300 25 100 5 950 9 200 9 250 12 800 17 100 28 900 6 250 9 800 11 000 13 800 19 000 29 200

f017.1 16.6 16.3 15.5 14.3 13.2 17.3 16.5 16.5 15.7 14.4 13.5 17.1 16.5 16.4 15.8 14.5 13.6 17.3 16.6 16.5 16.0 14.9 13.6 17.1 16.5 16.6 15.9 15.1 13.9 17.2 16.6 16.5 15.9 15.4 13.9

DU DDU

amax

bmin

D1max

r0max

rNmin

D2

(mm)

fmin

d a( )2

D a( )2

ramax

Dxmin

CYmax approx

max

max

max

max

120

130

140

150

160

1 1.1 1 2 2.1 3 1 1.1 1 2 2.1 3 1.1 1.5 1.1 2 3 4 1.1 1.5 1.1 2 3 4 1.1 2 1.1 2.1 3 4 1.1 2 1.5 2.1 3 4

4 300 4 300 3 800 3 800 2 800 2 400 4 000 3 800 3 600 3 600 2 600 2 200 3 600 3 400 3 000 3 000 2 400 2 200 3 400 3 200 2 800 2 800 2 200 2 000 3 200 2 600 2 600 2 600 2 000 1 800 2 600 2 600 2 400 2 400 1 900 1 700

2 400 2 400 2 200 2 200 2 200 2 200 2 000 1 800 2 000 1 900 1 900 1 800 1 700 1 800 1 700 1 700 1 700 1 600 1 600

5 300 5 000 4 500 4 500 3 400 3 000 4 800 4 500 4 300 4 300 3 200 2 800 4 300 4 000 3 600 3 600 3 000 2 600 4 000 3 800 3 400 3 400 2 800 2 400 3 800 3 200 3 000 3 000 2 600 2 200 3 200 3 000 2 800 2 800 2 400 2 000

6822 6922 16022 6022 6222 6322 6824 6924 16024 6024 6224 6324 6826 6926 16026 6026 6226 6326 6828 6928 16028 6028 6228 6328 6830 6930 16030 6030 6230 6330 6832 6932 16032 6032 6232 6332

ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZ ZZS ZZS ZZ ZZ ZZ ZZS ZZ ZZS ZZ ZZS ZZS ZZ ZZS ZZ ZZS ZZS ZZS ZZS ZZ ZZS ZZS

VV VV VV VV VV VV VV VV VV VV VV VV VV

DDU DDU DDU DDU DD DDU DDU DDU DD DDU DDU DDU DDU DDU DDU DDU DDU DDU DDU

2.50 3.30 3.71 5.69 2.50 3.70 3.71 3.30 3.70 5.69 3.30 3.70 3.30 3.30

1.9 1.9 3.5 3.5 1.9 1.9 3.5 1.9 1.9 3.5 1.9 1.9 1.9 1.9

137.60 147.60 163.65 193.65 147.60 161.80 173.66 161.80 176.80 193.65 171.80 186.80 186.80 196.80

0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6

0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

145.7 155.7 182.9 212.9 155.7 171.5 192.9 171.5 186.5 212.9 181.5 196.5 196.5 206.5

1.7 1.7 3.1 3.1 1.7 1.7 3.1 1.7 1.7 3.1 1.7 1.7 1.7 1.7

115 116.5 115 119 121 123 125 126.5 125 129 131 133 136.5 138 136.5 139 143 146 146.5 148 146.5 149 153 156 156.5 159 156.5 161 163 166 166.5 169 168 171 173 176

117 121 124.5 134 147 127 132 134.5 146 161 138 144 148.5 157 175 148.5 153.5 158.5 171.5 187 160 166 170 186 203 170.5 176 181.5 202 215.5

135 143.5 165 161 189 227 145 158.5 175 171 204 247 158.5 172 193.5 191 217 264 168.5 182 203.5 201 237 284 183.5 201 218.5 214 257 304 193.5 211 232 229 277 324

1 1 1 2 2 2.5 1 1 1 2 2 2.5 1 1.5 1 2 2.5 3 1 1.5 1 2 2.5 3 1 2 1 2 2.5 3 1 2 1.5 2 2.5 3

147 157 185 215 157 173 195 173 188 215 183 198 198 208

3.9 4.7 6.4 8.4 3.9 5.1 6.4 4.7 5.1 8.4 4.7 5.1 4.7 4.7

0.497 0.893 1.51 1.94 4.45 9.51 0.537 1.21 1.6 2.08 5.29 12.5 0.758 1.57 2.4 3.26 5.96 15.2 0.832 1.67 2.84 3.48 7.68 18.5 1.15 3.01 3.62 4.24 10 22.7 1.23 2.71 4.2 5.15 12.8 26.2


Remarks When using bearings with rotating outer rings, contact NSK if they are sealed, shielded, or have snap rings.

B 16

B 17

SINGLE-ROW DEEP GROOVE BALL BEARINGSBore Diameter 170 240 mmB r r jD jd jDa ra ra jda


C 0r0.172 0.345 0.689 1.03 1.38 2.07 3.45 5.17 6.89

e0.19 0.22 0.26 0.28 0.30 0.34 0.38 0.42 0.44 X 1 1 1 1 1 1 1 1 1

Fa e Fr Y 0 0 0 0 0 0 0 0 0

Fa >e Fr X 0.56 0.56 0.56 0.56 0.56 0.56 0.56 0.56 0.56 Y 2.30 1.99 1.71 1.55 1.45 1.31 1.15 1.04 1.00

Open Type

Shielded Type ZZS Factor{kgf}

Non-Contact Sealed Type VV Limiting Speeds (min 1)Grease OilOpen Z Open Z ZZ V VV

Static Equivalent Load Fa >0.8, P0 =0.6Fr +0.5Fa Fr Fa 0.8, P0 =Fr Fr Bearing NumbersOpen Shielded Sealed



Abutment and Fillet Dimensions (mm)

Mass(kg)

d170

D215 230 260 260 310 360 225 250 280 280 320 380 240 260 290 290 340 400 250 280 310 310 360 420 270 300 340 340 400 460 300 320 360 360 440 500

B22 28 28 42 52 72 22 33 31 46 52 75 24 33 31 46 55 78 24 38 34 51 58 80 24 38 37 56 65 88 28 38 37 56 72 95

rmin

Cr60 000 86 000 114 000 161 000 212 000 325 000 60 500 119 000 145 000 180 000 227 000 355 000 73 000 113 000 149 000 188 000 255 000 355 000 74 000 143 000 161 000 207 000 269 000 380 000 76 500 146 000 180 000 235 000 310 000 410 000 98 500 154 000 196 000 244 000 340 000 470 000

C 0r75 000 97 000 126 000 161 000 224 000 355 000 78 500 128 000 157 000 185 000 241 000 405 000 93 500 127 000 168 000 201 000 282 000 415 000 98 000 158 000 180 000 226 000 310 000 445 000 107 000 169 000 217 000 271 000 375 000 520 000 137 000 190 000 243 000 296 000 430 000 625 000

Cr6 100 8 750 11 700 16 400 21 700 33 500 6 200 12 100 14 700 18 400 23 200 36 000 7 450 11 500 15 200 19 200 26 000 36 000 7 550 14 600 16 400 21 100 27 400 38 500 7 800 14 900 18 400 24 000 31 500 42 000 10 000 15 700 19 900 24 900 34 500 48 000

C 0r7 650 9 850 12 900 16 400 22 800 36 000 8 000 13 100 16 000 18 800 24 600 41 500 9 550 13 000 17 100 20 500 28 700 42 500 10 000 16 100 18 300 23 000 31 500 45 500 10 900 17 300 22 100 27 600 38 500 53 000 14 000 19 400 24 700 30 000 44 000 63 500

f017.1 16.7 16.5 15.8 15.3 13.6 17.2 16.4 16.3 15.6 15.1 13.9 17.1 16.6 16.4 15.8 15.0 14.1 17.2 16

NSK Bearings

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Transcript of NSK Bearings